Drifting and by-pass valve



Dec. 28, "1926." 1,612,435

C. D. HILFERTY DRIFTING AND BY-PASS VALVE Original o 8. 1917 2 Sheets-Sheet 1 CHAFL E5. D. H/LFEPTL/ I N VEN TOR.

j BY J ATTORNEY Dec. 28 1926.

HILFERTY DRIFTING AND BY-PASS VALVE 2 Sheets-Sheet 2 Original Filed Nov. 8. 191

Patented Dec. 28, 1926.

entren- STATES ase PATENT OFFICE.

CHARLES 15. HLF1tRTfY, or w'EsTF'IE'Ln, NEW JERSEY, ASSIGNOR TO THE SUPER HEATER COMPANY,- or" NEW YORK, N. Y., A CORPORATION or DELAWARE.

DRIFTING"AND BY-PASS VALVE.

Original application filed November 8, 1917, Serial No. 200,920. Divided and this application filed. June 8,

1920. Serial No. 337,508.

My invention relates to locomotives and has particular reference to the class of valves known as drifting valves which are used on locomotives. In my invention I combine a valve of this kind with a by-pa'ss valve, i. e., a valve capable, under certain conditions, of establishing communication between the two ends of the cylinder. I provide by my invention a practical means of admitting drifting steam and cutting it off, and simultaneously respectively opening and closing the bypass. I" further provide an improved mechanism for automatically cutting off the drifting steam and closing the bypass when the engine is at rest. Other objects of my invention will appear as the description proceeds. I

The present case constitutes a division of my application 200,920, filed November 8th, 1917, which has been issued on August 31st, 1920, as Patent No. 1,351,168.

To understand the invention a reading of the following description in connection with the accompanying drawings will be suitieient. In these drawings Fig. 1 represents my invention applied to' a locomotive, only as much of the lat er being shown as is required to show the relation of my device to the parts of the locomotive.

Fig. 2 is another view showing a portion of the arrangement on a somewhat enlarged scale;

Fig. 3 shows the drifting and by-pass valve in longitudinal central section;

Figs. 4 and 5 show sectional views, taken through the axis of the control valve and at right anglesto each other;

Figs. 3, a, and 5 are on a still larger scale v with the space to the right of the large than Fig. 2;

Figs. (5 and 7 are two central longitudinal sectional views taken at right angles to each other of a modified form of the control valve. Referring to the form of my invention illustrated in Figs. 1 to 5, there is shown in Fig. 1 my device attached to a locomotive, only as much of the latter being shown" as is required to show the manner of attachment and working. Reference numeral 1 refers to the valve casing generally. 2 is the locomotive boiler, 3 and t are the cylin der and valve chest respectively, 5 is the link of a valve gear. These parts are of the ordinary or any preferred construction. The two ends of the cylinder are connected to each other by means of the by-pass 6,(3, the two parts of which lead from the two ends of the cylinder to the valve casing 1. Also connected with this valve casing is the pipe 7, its other end being connected to the steam space of the boiler. 8 is a globe valve in this pipe, while 9 is a Y from which a branch pipe corresponding to 7 leads to a valve easing corresponding to 1 and located on the other side of the locomotive.

It will be understood that while in the following description and in what has preceded reference is usuallymade to" only one cylinder, one valve chest, one drifting valve,

etc., there are corresponding duplicate parts on the opposite side of the locomotive.

Valve casing 1 is secured to the side of the smoke-box by means of a bracket 50. Valve casing 1 has a cylindrical bore 18 (see F 3) with ports 19 and 20, with which ports the pipes 66 of the by-pass communicate. The cylindrical bore 21', considerably larger than bore 18, is coaxial with the latter, and the differential piston valve 22 is fitted into these bores. The portion of the valve lying in bore 18 is hollow and has cast into it a circular series of port openings 23. The proportions of the parts just described are such that when the piston valve is in its position toward the left, as'

viewed in Fig. 3, the port openings are closed, but when'the valve is in" its position toward the right, these openings register with port 20, and the left edge of the hollow valve is about flush with the right edge of port 19.

A small opening 24 connects the hollow interior of the left portion of the valve piston 22. The right end of valve casing 1 is closed by the cover 26.

The valve 22, on account of its difl'erential feature, will be held in the position shown in Fig. 3 whenever the pressiu'c in chamber 25 is sensibly near that on the other side or higher.

To insure the proper position at any time of valve 22 I utilize a control valve 51. This is represented to a larger scale in the two sectional views of Figs. 4:" and 5. In the casing 52' of this control valve there is piston valve 58, the upper enlarged portion 54 of which reciprocates in the larger chamber 55', while its lower stemportion 56, of

loo

smaller diameter, extends into the cylindrical chamber 57, coaxial with 55. For a short distance below the piston 53 the stem 56 is of reduced diameter, as at 58. Also extending through the lower part of the easing 52 is the duct 50, which leads into chamber 55 and has located in it the check valve 60. This check valve opens outwardly from 55, and is pierced by a small hole 61.

Duct 62 leads to the atmosphere from the chamber 57, its inner end being so located that it opens into the annular space around the reduced portion 58 of stem 56, when the valve 53 is in its lower position, but is closed by the stem when valve 53 begins to rise.

Annular port 63 connects by means of passage 64 and pipe 65 with chamber of valve casing'l.

A small bleeder 66 leads from port 63 y to the lower surface of stem 56. Chamber 57 is connected to one of the steam ports of the engine cylinder by means of pipe 67, opening into it at 68. This is equivalent to tapping it into the steam chest, as the vacuum produced by the moving piston during drifting exists first of all in the cylinder.

The operation of this form of the device may be described as follows. When the locomotive is running normally, with the throttle open, steam from steam port 69 passes up through pipe 67 and duct 59, leaking through the small hole 61 in check valve 60, and fills chamber 55. This steam pressure keeps control valve 53 in its lower position against steam pressure on the lower end of the stem 56 and air pressure on the lower annular surface of 54L The valve in casing 1 is kept in its closed position, as in Fig. 3 by steam pressure in chamber 25, which steam has leaked in through small passage 24, the opposing steam pressure on the valve acting on a smaller surface.

lVhen now the engineer shuts the throttle, and a vacuum forms in the cylinder, the steam in. chamber in'nnediately leaves by way of passage 59, with the result that valve 53 is raised by atmospheric pressure. This establishes communication between chamber 25 and space 57 by way of pipe 65, passage 64, and port 63. The steam in 25 then escapes, and escapes faster than opening 2+1 allows fresh steam to leak in, with the result that the reduced pressure on the right overcome and valve 22 moves to the right. This puts the two ends of the main cylinder into communication and also allows drifting steam to be supplied, as in the first form of the device.

As a matter of fact, there is not, during drifting, anything like a constant condition of vacuum in the cylinder port passage. As the piston approaches the end of its stroke, the main valve is closed, and the pressure runs up. This pressure, however,

is not quickly transmitted to chamber 55, because check valve operates, and allows only a very small, gradual leakage through opening 61. Before any appreciable amount of pressure can accumulate in 55, the piston, on its return stroke, is again creating a vacuum and relieves this pressure. In effect the action is that of pumping out pressure from chamber 55, with a small seepage back through 61.

The function of bleeder 66 is to drain away any water and obviate the danger of freezing. It is of course made small enough so it does not conduct enough steam away from chamber 25 to infl ence the act-ion of the apparatus.

The modification of the control valve shown in Figs. 6 and 7 substitutes a dia phragm 70 for the piston 5%. Stem 56 moves with this diaphragm, and the action is identical with that of the form in Figs. 8 and 9.

In the case of locomotives having more than two cylinders, it will be understood that each cylinder may, if considered advisable, be equipped with my device.

While I have in the above fully described only one principal form of the device for carrying out my invention and one slight modification, other modifications are readily seen to be possible, and will be made in practice. These, however, inasmuch as they come Within the spirit of my invention, are meant to be covered by the terms of the subjoined claims.

What I claim is Y 1. In a drifting mechanism, the combination of a main engine cylinder; a valve casing; a pipe supplying live steam to the easing; two pipes leading from the casing and eon'in'iunicating with'the two cylinder ends respectively; a valve in the casing controlling said steam supplying pipe and the two connections to the cylinder ends, so that in one position'of the valve the three are in communication with each other and in the other position all communication betweei'i them is interrupted; and automatic means to oper ate the valve, said means being actuated by the difference in pressure in the steam supplying pipe and in one of the cylinder ends.

2. In a drifting mechanism, the combination of a main engine cylinder; a valve easing; a pipe supplying live steam to the casing; two pipes leading from the casing and communicating with the two cylinder ends respectively; a valve in the casingcontrolling said stean'rsupplying pipe and the two connections to the cylinder ends, so that in one position of the valve the three are in communication with each other and in the other position all communication between them is interrupted, automatic means to cause said valve to be actuated by pressure differences between the live steam supply lli) and cylinder end, said means including a diii'erential valve operating in response to pressure differences bet-ween the atmosphere and said cylinder end.

3. In a drifting mechanism, the combination oi a main engine cylinder; a valve casing; a pipe supplying live steam to the casing; two pipes leading from the casing and communicating with the two cylinder ends respectively; a dili erential valve in the casing controlling said steam supply and the two connections to the cylinder, so that in one position of the valve the three are in communication with each other and in the other position all connnunication between them is interrupted; said valve being subject on its smaller end to steam pressure from said first-named pipe, said pressure tending to put the valve into its first position; said valve being provided with a relatively small aperture leading from its smaller to its larger side whereby steam may flow slowly to the larger chamber, the pressure exerted by such steam tending to put the valve into its second position; a connection from the larger end of the valve casing to one cylinder end, said connection being substantially larger than said aperture; and an automatic valve in said last-named connection operating to open it when the average pressure in the cylinder end falls below a certain point and keepin it closed at other times.

4. In a drifting mechanism, the combi nation of a main engine cylinder; a valve casing; a pipe supplying live steam to the casing; two pipes leading from the casing and communicating with the two cylinder ends respectively; a differential valve in the casing controlling said steam supply and the two connections to the cylinder, so that in one position of the valve the three are in communication with each other and in the other position all communication between them is interrupted; said valve being subject on its smaller end to steam pressure from said first-named pipe, such pressure tending to put the valve into its first position; said valve being provided with a relatively small aperture leading from its smaller to its larger side whereby steam may flow slowly to the larger chamber, the pressure exerted by such steam tending to put the valve into its second position; a connection from the larger end of the valve casing to one cylinder end, said connection being substantially larger than said aperture; and an automatic differential valve in said last named connectlon comprising a housing with a large and a small chamber, a dilierential valve body reciprocable in said chambers, there being in the housing a duct leading from the main cylinder end to one end of the large chamber; a check valve in said duct opening away from the chamber; the housing having a further duct from the second end of the large chamber to the atmosphere, the end of the small chamber being in constant communication with the cylinder end.

CHARLES D. HILFERTY. 

